Techniques for embedding a hidden digital message (i.e. a digital watermark) in a host medium such as an image, audio or video are well known. Various known watermarking applications verify the presence of the watermark in a target image, audio or video medium. There are also various known techniques for detecting and extracting (i.e. reading) digital watermark signals. Many watermarking applications are based on the ability of some types of watermark signals to survive manipulations (e.g. rotation, scaling and digital/analog conversions) which tend to weaken watermark signals.